Mask



FIG. 1 is a top perspective view of a mask, showing my new design;

FIG. 2 is a bottom perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a right side view thereof;

FIG. 7 is a top view thereof; and,

FIG. 8 is a bottom view thereof.

The broken lines in the figures illustrate portions of the mask that form no part of the claimed design. The broken lines in the figures indicate the environmental structure that form no part of the claimed design. 

CLAIM The ornamental design for a mask, as shown and described. 